WO1996006264A1

WO1996006264A1 - Method and apparatus for steering a drill head

Info

Publication number: WO1996006264A1
Application number: PCT/FI1994/000360
Authority: WO
Inventors: Valto ILOMÄKI
Original assignee: Ilomaeki Valto
Priority date: 1994-08-19
Filing date: 1994-08-19
Publication date: 1996-02-29

Abstract

A method to steer and to adjust the direction of the drill head (12) of an apparatus drilling a tunnel or a hole, in which method a laser beam or similar projected from the tunnel starting point to the drill head is used to detect the position of the drill head and for drilling an equipment is used having a free opening from the said starting point to the drill head. The laser beam is received in the drill head with a rotating target (13) the rotating position of which is detected at least in one angular position of rotation by means of an angle sensor (25) and that information on deviation received at the said angular position from target (13) by means of measuring unit (14) is transmitted to drill head (12) steering devices (19, 20) to change the position of drill head supporting means (22, 24) with regard to outer tube (23).

Description

METHOD AND APPARATUS FOR STEERING A DRILL HEAD

This invention relates to a method accordinσ to Datent claims 1 and 2 and an apparatus accordinq to claim 7 for steerinq a tunnel drilling device.

Previously known is a.o. the use of a laser beam for steering of drilling equipment, e.g. from patent document GB 2 095 720, where it has been utilized for steering of relatively short sequentially arranqed tubes on drilling a tunnel with a great diameter. Optical devices are also known from patent document GB 2 157 421. Building a tunnel with a relatively small dia¬ meter, drilling within a diameter range of 100 - 600 mm, the change of direction of the drill head often becomes a problem, since mostly one cannot lay any additional pipelines along a finished tunnel from its starting point to the drill head. The available space in the tunnel is filled by the drilling appa¬ ratus and the drill waste conveying systems. Therefore, it is difficult to change the direction of the drilling apparatus if it deviates from its original, for instance due to the nature of soil.

By means of the method and apparatus according to this invent¬ ion an unexpected imrovement in this respect is achieved and the invention is characterized in what is presented in the enclosed patent claims.

The major advantage of this invention can be considered that for steering the drill head no additional tube or cable from the tunnel starting point to the drill head must be installed in the tunnel. The drill head contains all adjusting devices and actuators reguired for changing its direction and the required energy or means to produce the power needed for the steering.

In the following the invention is disclosed with reference to the enclosed drawinq, where Fig. 1 is a side view of the drilling apparatus rear part; Fig. 2 is a side section of the head of the drilling apparatus; Fig. 3 is section A-A of figure 1; Fig. 4 is a position detecting target board with an angle sensor; Fig. 5 is a front view of a not-rotating target; Fig. 6 is a not-rotating target placed eccentrically in the tunnel.

Figure 1 shows the drilling apparatus rear part, which has a body 2 moving along rail 1 in the the same direction the tunnel is pushed. An outer tube 9 including a compressed-air pipe 5 furnished with spiral ribs is pushed into the tunnel. This compressed-air pipe is rotated by a motor 3 and a gear 4. Com¬ pressed air is fed into rotating pipe 5 by means of a packed collar 6. In the rear end of collar 6 there is a glass 11, through which a laser beam is projected into pipe 5. A laser gun 7 is illustrated in the figure. Conveyed by the rib system, drill waste enters along outer tube 9 and and exits through an opening in the body 2 as shown in the figure.

Figure 2 shows drill head 12 comprising a drill bit and a ham¬ mering device (not shown). Compressed air is conveyed into the drill head, where it drives the hammering device and is dis¬ charged through the opening in the drill bit to the front side of the bit and back again into drill head 12 while conveying drill waste along with it. From the rear of drill head 12 com¬ pressed air and drill waste are exhausted into outer tube 9.

The outer tubes 9 and 23 are not rotated but only pushed into the drilled bore hole. Drill head 12, which is rotating, is fastened with bearings from its rear end to outer tube 23 by means of rolls 15 and arms 16 supporting the same. The front part of drill head is secured to outer tube 23 by means of a movable supporting roll system 24. Rolls 22 of the system lean directly against the drill head surface. Outer circle 24 of the roll system is propped against the inner face of outer tube 23 by means of wedge-shaped movable parts 21, which are interconnected by an arm 29 that has its articulated points 30 in the outer tube. Therefore, if the upper part 21 is pushed forward by power unit 20, the lower part 21 moves backward in proportion. Thus it is possible by means of power unit 20 to force circle 24, which functions as a bearing, eccentrically into outer tube 23. In the embodiment illustrated in the figure upward eccentricity can be generated. If there is on the sides of bearing circle 24 another pair of parts 21 and a power unit to drive them, lateral eccentricity can also be produced. For¬ ward shiftover of bearing circle 24 is prevented by a support¬ ing ring 31.

Figure 3 shows a section at bearing circle 24 where rolls 22, four altogether, can be seen as well as articulated points 30 of arms 29 on the sides of the outer tube

In figure 4 the target board 13 detecting the laser beam is still in the rear of drill head 12 and one tries to keep it the target of the laser beam all the time during drilling. The target board as well as the measuring unit 14 behind it rotate while drilling. In order to determine the direction of deviat¬ ion, a connection between the angular position of the target and the angular position of adjusting devices 20,21 must be arranged. This has been settled so that the target board reacts to the laser beam only when the board 13 is in a position where sensor 25 rotating along with it is in the lower position of rotation. The sensor gives a signal of its low position by means of voltage over electric cables 27, the circuit of which voltage is closed only when cables 27 are switched on by a mercury drop 26. This takes place in sensor lower position with drop 26 in balance in the sensor centre. At this instance laser beam 10 that has impinged on target board 13 and its hit on any sector 28 are noted. If the impingement is at a sufficient dis¬ tance off the centre, a deviation correcting impuls is given to respective adjusting device 21 on respective sector 28 over the measuring and steering units 14 and 19. For instance, the adjusting device 20 retains the eccentricity of bearing circle 24 with regard to outer tube 23 as long as the laser beam is moving to the permitted centre of the target board. If four sectors of the target board are used for adjustement, also laterally, the embodiment in the figur must have also for the lateral adjustments a pair of movable wedges 21 and an actuator to drive them.

Measuring unit 14 associated with target board 13 contains electric functions and it is advantageous in one embodiment to place a power source, for instance a battery, in unit 14. For transmission of deviation data to steering unit 19, a radio transmitter or some other wireless transmitter can be used.

A battery can also be used as power source in steering unit 19, energy can be produced in the way illustrated in the figure, i.e. pressing wheel 18 against the drill head, whereat electri¬ city can be produced by using a generator and also mechanical energy. Thus, as power unit 20 a mechanical, linearily moving rod or a magnetically generated motion can be used, as well as pneumatic cylinder 20, for which compressed air is available in the drill head. Yet, the steering of adjusting devices is advantageously carried out by electric power.

Figure 5 shows a non-rotating target 32 fastened with bearings in drill head 12 so that said target 32 can be non-rotating. Due to gravitation, target 32 remains non-rotating by means of a weight 33 in the target lower edge. Uninterruptedly, target 32 can receive the laser beam and, similarily, the direction of the drilling apparatus can be adjustable. Lateral and vertical adjustment of the drilling apparatus is possible according to the four sectors 28 in the illustrated target 32.

Figure 6 shows a non-rotating target 32 eccentrically arranged outside centre pipes 5 and 34. Target 32 and its body are fastened with bearings, for instance with regard to rotating tube 34, so that the target remains immobile while the tube is rotating. In this case, due to its own mass and possible extra mass, target 32 remains immobile in the lower edge while pipes 5, 34 and even protective tube 9 are rotating. A laser beam impingement on any of sectors 28 indicates directly the direct¬ ion of deviation.

Instead of gravity, the target can be kept non-rotating with regard to any of the tubes 5,34,9 also by means of a rotating motor. The apparatus contains then a pilot circuit to detect the angular position, for instance by means of an angle sensor, and the target is then kept non-rotating by means of the target-rotating motor regardless of the rotation of tubes 5,9 or 34.

Drill head 12 is steered only by projecting a laser beam or a similar optical beam at the drill head along an opening formed in pipe 5. For steering the drilling apparatus, no other cable or tube must be taken to the drill head.

Claims

PATENT CLAIMS

1. A method to steer and to adjust the direction of the drill head (12) of an apparatus drilling a tunnel or a hole, in which method a laser beam or similar projected from the tunnel start¬ ing point to the drill head is used to detect the position of drill head (12) and by means of received information on devi¬ ation the position of drill head (12) supporting means (22,24) with regard to outer tube (23) is changed and for drilling an equipment is used containing a free opening from said starting point to the drill head, characterized in that a laser beam (10) or similar is received in the drill head by a rotating target (13), the rotating position of which is detected at least in one angular position of rotation by means of an angle sensor (25) based on gravity and rotating along with target

(13) and that information on deviation received at the said angular position from target (13) by means of a measuring unit

(14) is transmitted to the drill head (12) steering devices (19,20).

2. A method to steer and to adjust the direction of the drill, head (12) of an apparatus drilling a tunnel or a hole, in which method a laser beam or similar projected from the tunnel start¬ ing point to the drill head is used to detect the position of drill head (12) and by means of received information on deviat¬ ion the position of drill head (12) supporting means (22,24) with regard to outer tube (23) is changed and for drilling an equipment is used containing a free opening from said starting point to the drill head, characterized in that a laser beam (10) or similar is received in the rotating drill head with a not-rotating target (32) in the drill head the position of which target is steered to remain constant by means of gravity or an angle sensor (25), based on the effect of gravity, and by steering devices, and the information on deviation received by target (32) is transmitted to drill head (12) steering devices (19,20).

3. A method according to patent claim 1 or 2 characterized in that the information on deviation from measuring unit (14) to the steering-adjusting unit (19) is sent by wireless trans¬ mission.

4. A method according to any of the patent claims 1 - 3 charac¬ terized in that the direction of the drill head is changed in moving the supporting means (22,24) of drill head bearings into an eccentric position with regard to outer tube (23).

5. A method according to any of the above patent claims 1 - 4 characterized in that energy required for steering and for actuators (19,20) is produced, at least partly, in the drill head.

6. A method according to patent claim 5 characterized in that energy is produced from the mutual difference of motion and speed of parts (12,13) in the drill head.

7. An apparatus to apply the method according to patent claim 1 or 2 characterized in that it contains: a laser beam source (7), the beam of which can be projected to drill head (12) through a free opening in the drilling apparatus; a rotating target (13) or a not-rotating target (32) in the drill head to receive the laser beam; a measuring unit (14) to measure the deviation of the drill head; and that there is, in association with measuring unit (14) and target (13) or (32), an angle sensor that gives an impulse at least from one angular position in target (13) in order to measure deviation in said angular position or means (33,35) to keep target (32) non-rotating by means of gravity, and means to transmit information on deviat¬ ion to the steering unit (19) and adjusting devices (20,21) in order to change the direction of the drill head with regard to outer tube (23) .

8. An apparatus according to patent claim 7 characterized in that the drill head contains the means to produce energy from the mutual motion of two parts in the drill head.

9. An apparatus according to patent claim 7 or 8 characterized in that the apparatus comprises a free space leading to the drill head and formed inside the rotating compressed-air pipe (5) to project laser beam (10) to drill head (12) from the steering station in the rear part of the drilling apparatus.

10. An apparatus according to patent claim 7 or 8 character¬ ized in that the free opening is outside the rotating compres¬ sed-air pipe (5).